1. Field of the Invention
The present invention relates to the use of salicylic acid derivatives as stabilizers for oil-in-water emulsions, as well as to cosmetic and/or dermatological emulsions containing such a derivative. The present emulsions are intended in particular for the treatment or care of the skin, both of the human face and body, including the scalp and the nails, and even more especially for treating and/or combating acne, greasy skin with a tendency towards acne, and the ageing (wrinkles, fine lines, complexion) and pigmentation of the skin.
2. Discussion of the Background
It is known to use salicylic acid derivatives as keratolytic agents for treating acne and as an anti-ageing agent in cosmetic and/or dermatological compositions (see FR-A-2,581,542 and EP-A-378,936).
These derivatives are of great value, given their biological effects on the skin. They make it possible in particular to impart a light and radiant complexion to the face, and thus a healthy look and a smooth and younger appearance, as well as making it possible to remove comedones caused by acne.
However, their use poses a problem insofar as they are in crystalline form and insofar as they are soluble neither in water nor in the oils traditionally used in the cosmetic and dermatological fields, such as mineral oils (petrolatum, paraffin).
Thus, if they are introduced as they are into cosmetic and/or dermatological compositions, they remain in the form of crystals, thereby making the use of the composition containing them inefficient for treating the skin.
On the other hand, these derivatives are soluble in lower alcohols such as ethanol or isopropanol, Guerbet alcohols or in solvents such as octyldodecanol, certain glycols, short-chain (&lt;C12) fatty alcohols, which are polyoxyethylenated or polyoxypropylenated, or alternatively short-chain (&lt;C12) esters.
The lower alcohols have the drawback of drying and irritating the skin; they are poorly tolerated by sensitive or fragile skin, especially in repeated applications. It is thus preferred to avoid using them in body- and/or face-care products.
Moreover, the short-chain fatty alcohols and fatty esters, as well as certain glycols, make it possible to solubilize these derivatives, leading to the deep-down penetration of active agents into the skin, which is not necessarily desirable for care products.
Currently, it is increasingly sought generally to limit the use of solvents in skin-care products, since these solvents are not always well tolerated and may lead to irritation when they are used in too large an amount.
The inventors have thus sought to formulate the salicylic acid derivatives in compositions containing the least possible amount of solvents.
Moreover, these derivatives have the major drawback of causing stinging, itching and pulling sensations after their application, which may lead to a level of discomfort such that their use by individuals with sensitive skin is often prevented. This discomfort is due in particular to the acidic functional group of these derivatives.
Thus, there is a need for cosmetic and/or dermatological compositions based on a salicylic acid derivative, which imparts a healthy look and rejuvenation to the skin and also removes comedones, without resulting in the above-mentioned drawbacks.